Adhesive composition and production method for adhesive composition

Abstract

It is provided an adhesive composition having a high biobased content and having a moderate adhesive property and high heat resistance and a method for producing the same, and an adhesive composition including: a block copolymer (X) including a polymer block (A) containing a structural unit derived from an aromatic vinyl compound and a polymer block (B) containing a structural unit derived from a conjugated diene compound, and a tackifier (Y), in which the block copolymer (X) includes, as the polymer block (B), at least one polymer block (B-1) containing a structural unit derived from β-farnesene, and the block copolymer (X) include at least one selected from the group consisting of an unhydrogenated block copolymer (X0) which is a block copolymer that is not hydrogenated, and a hydrogenated block copolymer (X1) which is a hydrogenated block copolymer and has a degree of hydrogenation of less than 50 mol %.

1 . An adhesive composition comprising: a block copolymer (X) including a polymer block (A) containing a structural unit derived from an aromatic vinyl compound and a polymer block (B) containing a structural unit derived from a conjugated diene compound, and a tackifier (Y),
 wherein the block copolymer (X) includes, as the polymer block (B), at least one polymer block (B-1) containing a structural unit derived from β-farnesene, and   the block copolymer (X) includes at least one selected from the group consisting of an unhydrogenated block copolymer (X0) which is a block copolymer that is not hydrogenated, and a hydrogenated block copolymer (X1) which is a hydrogenated block copolymer and has a degree of hydrogenation of less than 50 mol %.   
     
     
         2 . The adhesive composition according to  claim 1 , wherein a content of the tackifier (Y) is 50 to 170 parts by mass with respect to 100 parts by mass of the block copolymer (X). 
     
     
         3 . The adhesive composition according to  claim 1 , wherein the block copolymer (X) does not contain a diblock composed of the polymer block (A) and the polymer block (B), or the content of the diblock in the block copolymer (X) is more than 0% by mass and less than 60% by mass. 
     
     
         4 . The adhesive composition according to  claim 1 , wherein at least one selected from the group consisting of the unhydrogenated block copolymer (X0) and the hydrogenated block copolymer (X1) having a degree of hydrogenation of less than 50 mol % is crosslinked. 
     
     
         5 . The adhesive composition according to  claim 1 , wherein the block copolymer (X) has a glass transition temperature (Tg) of −52° C. or lower. 
     
     
         6 . The adhesive composition according to  claim 1 , further comprising at least one selected from the group consisting of a liquid rubber component (Za), a biomass-derived plasticizer (Zb), and a synthetic plasticizer (Zc). 
     
     
         7 . The adhesive composition according to  claim 1 , further comprising a liquid rubber component (Za), wherein the liquid rubber component (Za) comprises at least one selected from the group consisting of an unhydrogenated liquid rubber (Za0), which is a liquid rubber that is not hydrogenated, and a hydrogenated liquid rubber (Za1), which is a hydrogenated liquid rubber and has a degree of hydrogenation of 90 mol % or less. 
     
     
         8 . The adhesive composition according to  claim 1 , wherein a 180° peel strength measured in accordance with JIS Z 0237:2009 under conditions of a temperature of 23° C. and a peel rate of 200 mm/minutes is 10.0 N/25 mm or more. 
     
     
         9 . The adhesive composition according to  claim 1 , wherein a shear adhesion failure temperature (SAFT) calculated from a falling time of a weight in accordance with ASTM D3654M:2019 under conditions of an adhesive area of 25 mm×25 mm, a weight of 500 g, a temperature range of 40 to 205° C., and a rate of temperature increase of 0.5° C./minutes is 200° C. or higher. 
     
     
         10 . The adhesive composition according to  claim 1 , wherein a biobased content of the adhesive composition measured in accordance with ASTM D6866-21 is 10 to 100% by mass. 
     
     
         11 . The adhesive composition according to  claim 1 , wherein a vinyl bonding amount in the polymer block (B-1) is 3 to 20 mol %. 
     
     
         12 . The adhesive composition according to  claim 1 , wherein the content of the polymer block (A) in the block copolymer (X) is 40% by mass or less. 
     
     
         13 . A method for producing the adhesive composition according to  claim 1 , the method for producing the adhesive composition comprising:
 (I) dissolving the block copolymer (X) and the tackifier (Y) in a solvent and then distilling off the solvent; or   (II) kneading the block copolymer (X) and the tackifier (Y).